The invention concerns in particular these generally robotized vehicles whose central body is elevated and whose support on the ground is effected by vertical legs. During locomotion, the legs are alternately raised and lowered so that the vehicle remains constantly in support on certain legs. Moving forward is effected by deforming the transmissions of the legs so as to move the central body and the raised legs with respect to the legs connected to these deforming transmissions. Contrary to the case with the majority of vehicles, the legs in contact with the ground do not move on the latter by rolling or sliding.
The transmissions have a geometrical constitution allowing for converting a circular movement produced by a motor into a horizontal rectilinear leg movement, the periodic raising and lowering of the legs being effected by other means.
There are various transmissions to convert a circular movement into a varying movement or vice versa. Many of these present drawbacks, especially as regards their mechanical efficiency. The ones which have been retained to form part of the invention exclusively use interjoined bars. It ought to be mentioned that several transmissions integrated in the invention and having as one characteristic feature a degree of freedom are already known, the trajectory of one of the points being a circle and the trajectory of another point being a straight line.
Generally speaking, the transmission includes a main system of interjoined bars and including a first point joined to the solid, a second point joined to the member, a crank forming part of the bars and joined to the solid at a third point and to the other bars at a fourth point, this crank having a length equal to the distance between the first and third points so that a movement for rotating the crank around the third point is expressed by a rectilinear movement of the second point.
The main system is completed by an additional system of bars joined to the solid at a fifth point and to the member at a sixth point; the additional system is constituted in such a way as to have an identical chain of bars between the sixth and fifth points identical at a nearby translation to a chain of bars of the main system between the second point and a seventh point where the main system is joined to the solid; this seventh point shall generally be merged with the first or the third point. Finally, linking bars are disposed between the two systems so that both the systems have a degree of freedom and the two chains of bars deform identically. In accordance with the invention, the transmission is completed by a motor system ending at the third point and adapted so as to have the crank rotate around this point. The transmission may thus be driven with a small amount of energy and the original forces of the second joint and perpendicular to its displacement, such as the support reactions of the member on the ground, do not provoke any torque on the motor, the latter thus able to be a lower-powered motor.
The linking bars often include stanchions parallel to a straight line passing through the second and sixth points and which each extend between one joint of the bar chain of the main system and one joint of the bar chain of the additional system and are joined to the chains of bars with these joints. A stanchion then frequently ends at the fourth point.
Another simple conception is one where the two systems are identical.
The invention also concerns a vehicle including a central body and legs resting on the ground and also provided with the transmissions defined as previously with each of these transmissions uniting the central body to a respective leg. The central body and the leg is equivalent to the solid and to the member or vice versa. The transmissions are disposed in such a way that the second points are moved parallel to the ground. Furthermore, the legs may be raised from the ground by elevating means.